1. Field of the Invention
The present invention relates generally to a method of applying a surface finish on a metal substrate. More particularly, the present invention relates to a method of preparing cold mill work rolls for use in applying the surface finish on a metal substrate.
2. Description of Related Art
The typical choice of material for architectural panel applications is a brushed stainless steel finished product. It is the preferred material primarily due to its shiny surface finish, thus making it popular for uses involving decorative applications, interior furniture, as well as the food industry. The use of the stainless steel brush finish look has expanded beyond architectural panel applications. Other applications include office furniture, lighting fixtures, door hardware, door kick plates, housewares, ceiling tiles, wall panels, nameplate and automotive trim applications, architectural composite applications, and the like. However, a viable alternative for stainless steel for use in such applications is aluminum. Aluminum has desirable properties that make it a beneficial alternative to stainless steel, such as being lighter, having better formability, as well as having a durable corrosion-resistant finish. Yet, one of the factors in delaying the use of aluminum instead of stainless steel in various applications is the perception that aluminum lacks the aesthetic stainless steel surface finish.
Much of the prior art in the field deals with methods of producing shiny, textured, or rough surfaces on metal. For example, U.S. Pat. No. 4,996,113 to Hector et al. is directed to a method for rolling metal material to enhance the brightness of the material. U.S. Pat. No. 5,508,119 to Sheu et al. is directed to a method of making a strip product having a specific textured surface. U.S. Pat. No. 5,789,066 to De Mare et al. is directed to a method of producing metal sheets or strips by cold reduction rolling of the metal sheet or strip with a pair of work rolls. U.S. Pat. No. 5,799,527 to Kenomochi et al. is directed to a method for producing a stainless steel sheet in which the steel sheet is cold rolled using a work roll. U.S. Pat. No. 5,998,044 to Limbach et al. is directed to an aluminum sheet that is suitable for use with the lithographic sheet support. U.S. Pat. No. 6,153,316 to Shannon is directed to mechanically textured aluminum alloy sheets that possess photometric properties. U.S. Pat. No. 6,177,206 to Sullivan et al. discloses polishing the surface of aluminum sheets for use as airplane parts. However, none of these prior art methods address how to obtain a surface finish like that of brush finish stainless steel on metal, such as non-ferrous alloys. The disclosures of the foregoing listed patents are incorporated into this disclosure by reference.
Thus, a need exists for a method of applying a surface finish on a metal substrate, such as aluminum or aluminum alloy sheet, that mimics the look of brush finish stainless steel. Additionally, a need exists for a method of preparing work rolls for applying the stainless steel finish look on a metal substrate, which has improved properties over stainless steel currently favored in the art.
The present invention is generally directed to a method of applying a surface finish on a metal substrate. More particularly, the present invention is directed to a method of applying a stainless steel look finish to a metal substrate, such as aluminum or aluminum alloy sheet. The present invention is further directed to methods of preparing cold mill work rolls for use in forming the desired surface finish on a metal substrate.
Preferably, the method of preparing the work rolls begins with placing a work roll on a grinder. The next steps include truing and roughening the work roll, and performing at least one finishing pass on the work roll. The method may include the step of comparing the surface roughness value of the work roll with a pre-designated or desired surface roughness value specification. If the surface roughness value of the work roll is not within the pre-designated or desired surface roughness value specification, the method may include the step of performing additional finishing passes. Additionally, at least two finishing passes may be performed. The method may also include the step of inspecting the work roll for defects and uniformity. The finished work roll may have a surface roughness value of between about 62-79 microinches Ra. The method of preparing cold mill work rolls, in another embodiment of the present invention, may further include the step of sanding the work roll. The finished work roll in this embodiment may have a surface roughness value of between about 40-45 microinches Ra.
The metal substrate may be aluminum or an aluminum alloy sheet. The metal substrate may have a gauge thickness of between about 0.004xe2x80x3-0.125xe2x80x3 and a width of between about 1xe2x80x3-69xe2x80x3 and, preferably, between about 15xe2x80x3-60xe2x80x3. The surface finish preferably has a stainless steel brush surface appearance.
The present invention is also a method of applying a surface finish on a metal substrate and generally begins with placing a work roll on a grinder. The work roll then undergoes truing and roughening. At least one finishing pass is performed on the work roll to obtain a desired surface roughness. The work roll is then inserted into a cold mill, and the metal substrate is then cold rolled with the work roll to achieve the desired surface finish of the metal substrate.
The method may further include the step of sanding the work roll. The metal substrate may have a gauge thickness of between about 0.004xe2x80x3-0.125xe2x80x3. Additionally, the metal substrate may have a gauge thickness of between about 0.005xe2x80x3-0.063xe2x80x3. The applied surface finish preferably has a brushed stainless steel surface appearance. The surface finish of the metal substrate has a surface roughness value of between about 60-95 microinches Ra. Additionally, a cold rolled metal sheet, including a cold rolled aluminum or aluminum alloy sheet, may be made utilizing this method.
Further details and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the drawings.